I've put some thought into that and I have a pretty simple answer: You can't!
We will never know what the player characters feel about anyone. What we can do, however, is manipulate the players and how they think.
I've reviewed my past campaigns, and players tended to like NPCs who displayed one or more of these qualities:
- Were funny
- Had skills that complemented the party
- Gave them stuff
- Were fun to interact with
- Did them favors
- Fight alongside them
- Easy to remember
Looking at that list now, it sounds pretty selfish, but I could say the same things about my close friends - we pay for each other's drinks, owe each other favors, talk about things, and come from a wide variety of complementary backgrounds.
Players tend to dislike NPCs who display these qualities:
- Have killed a PC in the past
- Want favors for no reward
- Are trying to kill the PCs
- Are in any way connected to the PC's backstory
Interestingly, I was also able to gather enough information to compile a short list of traits they merely distrust:
- Have ever tried in the past to kill the PCs
- Act utterly altruistic
- Have lengthy, complex backstories
- Have goals which are not immediately discernable
- Adventure with the party for some time without proving themselves to be an enemy or ally
Interesting! I think we can safely define these archetypes based on a few handy Star Wars characters:
- Players tend to like the "Han Solo," a loveable rogue with a reliable skillbase
- Players tend to dislike the "Jabba," who wants something for nothing and is an unpleasant reminder of who they once were
- Players tend to distrust the "Lando, but the Lando from Empire, not General Lando," which is interesting because traditional writing dictates this is the most realistic type of character
I'm thinking about other characters from Nerd Mythos and how they might be treated by a typical roleplaying party...
- C3PO: Dislike; annoying and worrisome, but occasionally useful. Best used as a mostly-invisible NPC
- Obi-Wan: Distrust; his motives are hard to determine and I don't like that he always volunteers for solo missions
- Princess Leia: Like; it was really funny when she made fun of Luke and she's a pretty good shot, let's not dump her at the next town
- Gandalf: Distrust; so he says he wants to save the world but I don't get his stake in it
- Mal Reynolds: Dislike; I hate that he tries to negotiate with us every time he fucks up a job.
- Jayne Cobb: Like; he's funny and dumb and I'd rather fight with him than against him.
- River Tam: Distrust; she's nuts and kind of creepy.
So, to recap, you shouldn't worry about what kind of people the PCs like; worry about making the players like them.* A trick on this subject is, the players only have the information you give them - if you really, really need the players to trust someone, then it's easy to tell them "your character trusts them."
*If you play in a group that's really super deep into roleplaying, this really isn't the blog for you, but I hope you stick around.